Mechanical Properties Study Of Bonding Interface Between Steel And Concrete Under Wet-thermal Condition

Paste steel reinforcement also known as bonding steel method,the principle is bonded the steel plate and concrete with the glue,it makes that the steel plate work with the concrete structure.This method won't change the structural system and the force form of the structure,the overall stiffness of the original structure and its ability to crack can be improved due to the excellent tensile strength of steel plate,so that the bonding steel method is wildly used in the reinforcement engineering.The mechanical properties of the adhesive surface is directly impacted by the failure mechanism of concrete structure.It has a practical significance and scientific value that analyze the durability of the adhesive surface under the hot and humid environment.This article relies on the construction technology project of ministry of transport“the key technology research on durability of the girder bridge after bonded reinforcement under coupling load(No.2015318814190)”,discussed the change of adhesive surface's mechanical properties influence by the hydrothermal environment rely on the experimental study.The main research contents and results are as follows:1 An accelerate method was put forward to simulate the hot and humid environment test according to the characteristics of the subtropical environment of southwest of China.Discussed the effect of hot and humid environment for shear bond properties of steel and concrete structures by the double shear test.The result indicates that hot and humid environment on the interfacial bonding properties between the steel and concrete structures had a negative impact.The mean ultimate load of the group(60?/95%RH/5d)compared to(25?/95%RH/5d)decreased 14.6%.The mean ultimate load of the group(60?/95%RH/5d)compared to(60?/85%RH/5d)reduced by about1%.Effect of temperature with respect to the bond properties of the interface is larger than the degree of influence of humidity.When the temperature and humidity increases,interface of bonding properties downward trend is most evident.The study also found that as the role of the hot and humid environment,the role of shear bond strength steel and concrete interface,strain level of development,the local average shear stress and bond stiffness were reduced to varying degrees.2 Get mechanical properties of the RC beams which is strengthened by bonded steel by the Static load test used the MTS system,the process of destruction and morphological were described during the experimental beam section.The resultindicates that the ultimate load,plate strain,tensile reinforcement strain will reduce by the hot and humid environment,and the longer duration of test,the effect is more obvious.3 It is found that the single-line model can be used to bond-slip analysis in the humid environment test through data analysis.Bond-slip model steel and concrete interface was set up depend on the single-line model,and the model considered the temperature,humidity and the coupling of temperature and humidity.